Laparoscopic or minimally invasive surgery includes the use of several relatively small ports into the abdomen by which different types of instrumentation and accessories are introduced and used for different surgical interventions (usually performed under endoscopic vision). Although usually considered superior in several aspects to open surgery, the use of plurality of 5 to 15 mm ports still leads to local pain, scars, and possibly port related complications such as hernia in scars and the need for one or two assistants in addition to the surgeon. Laparoscopic methods and surgical device are described, for example, in U.S. Pat. Nos. 5,980,493, 7,593,777 and 7,316,699, the disclosures of which are fully incorporated herein by reference.
In a relatively new laparoscopic approach commonly referred to as “needlescopy”, the laparoscopic ports are replaced with small incisions, usually between 2 to 3 mm in diameter. Narrow guide tubes are inserted into the small incisions and tiny surgical instruments are provided and manipulated through the tubes. The small instruments have very slender tips which make dissection and tissue maneuveration more difficult. Furthermore, the instrument tips may have a greater tendency to break and their removal may be cumbersome and difficult. The needlescopic surgery is performed under visualization made by a small television camera, replacing the traditional laparoscope which is substantially greater in size (commonly 5-10 mm in diameter) and contains illumination capabilities, that is introduced via a relatively large trocar unit, usually via the umbilicus. The small television camera, usually 3 mm or less in diameter, may be seen inferior considering its ability to capture and transfer high definition (HD) visual data, with respect to the traditional laparoscopes, due to its miniature size. A miniature camera is subjected to carry a smaller sized video sensor which inherently provides smaller resolution due to the decreased number of effective pixels. In order to achieve HD video resolution using approximately 5 μm pixels size the minimal active sensor surface should be about 8 mm the diameter, whereas in RGB format using approximately 2.5 μm pixels size, the minimal effective sensor area should be at least about 4 mm the diameter.
Due to the smaller effective size of the pixel, the amount or flux of the captured illumination may also be seen inferior, hence further affecting video quality. Currently, the needlescopic approach applies a plurality of thin optical fibers transferring illumination into the body cavity from external illumination source(s), due to excessive reduction of the transmitted light, as with respect to traditional laparoscopes built-in illumination.
A miniature camera may also be suffering from a smaller field-of-view (FOV), usually provided between 75° to 90° in standard laparoscopes, due to its use of a small diameter objective lens. Furthermore, a surgeon may also prefer a greater depth-of-field (DOF), which may be inherently compromised with a smaller lens, so that tissues and organs in background to the target location being in-focus will not be too blurred to identifying and monitoring.